linux-kernel - [PATCH] mm, vmpressure: remove redundant check in vmpressure()

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Date:   Wed, 19 Apr 2023 09:20:07 +0000
From:   Haifeng Xu <haifeng.xu@...pee.com>
To:     mhocko@...e.com
Cc:     hannes@...xchg.org, roman.gushchin@...ux.dev, shakeelb@...gle.com,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Haifeng Xu <haifeng.xu@...pee.com>
Subject: [PATCH] mm, vmpressure: remove redundant check in vmpressure()

There are three places, vmpressure_prio(), shrink_node_memcgs() and
shrink_node(), which invoke vmpressure(). But only shrink_node_memcgs()
sets tree to false and the memcg used in it is not NULL, so we don't
check it again in vmpressure().

Signed-off-by: Haifeng Xu <haifeng.xu@...pee.com>
---
 mm/vmpressure.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index b52644771cc4..3e4251a55e56 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -284,7 +284,7 @@ void vmpressure(gfp_t gfp, struct mem_cgroup *memcg, bool tree,
 		enum vmpressure_levels level;
 
 		/* For now, no users for root-level efficiency */
-		if (!memcg || mem_cgroup_is_root(memcg))
+		if (mem_cgroup_is_root(memcg))
 			return;
 
 		spin_lock(&vmpr->sr_lock);
-- 
2.25.1